Top stories: bees doing math, the link between gut bacteria and mood, and a potato breeding revolution

Bees ‘get’ addition and subtraction, new study suggests

If math is the language of the universe, bees may have just uttered their first words. New research suggests these busybodies of the insect world are capable of addition and subtraction—using colors in the place of plus and minus symbols. The bees got the correct answer 63% to 72% of the time, depending on the type of equation and the direction of the right answer—much better than random guesses would allow.

Evidence mounts that gut bacteria can influence mood, prevent depression

Of all the many ways the teeming ecosystem of microbes in a person’s gut and other tissues might affect health, its potential influences on the brain may be the most provocative. Now, a study of two large groups of Europeans has found several species of gut bacteria are missing in people with depression. The researchers can’t say whether the absence is a cause or an effect of the illness, but they showed that many gut bacteria could make substances that affect nerve cell function—and maybe mood.

This spud’s for you: A breeding revolution could unleash the potential of potato

Around the world, enhancing the potato has become a high priority. It is the most important food crop after wheat and rice. Keeping up with the demand means adapting the potato to various soils and climates. It must also resist new threats from pests, disease, heat, and drought. To find potatoes that can cope with those challenges, researchers and Peruvian farmers are testing dozens of the 4350 locally cultivated varieties, or landraces, kept in refrigerated storage at the at the International Potato Center’s gene bank in Lima.

Watch a maggot ‘fountain’ devour a pizza in 2 hours

Scientists now have a better sense of how maggots gobble food so quickly, a possible boon for sustainable food production. Researchers recorded black soldier fly (Hermetia illucens) larvae chowing down on orange slices and found that despite the appearance of chaos the larvae moved like water being pumped through a fountain. The researchers say better understanding the process could help grub farming companies scale up and turn even more food waste back into food.

Bug bombs don’t get rid of bugs, study suggests

In the United States alone, we spend more than $2.5 billion a year trying to rid our homes of cockroaches and other pests—but a new study says some of us may be doing it all wrong. The peer-reviewed study tested the effectiveness of baits, gels laden with insecticide, and bug bombs, devices that “fog” a room with an insect-killing aerosol. For at least one pest, the common German cockroach (Blattella germanica), bombs don’t work, says the study, but baits do.